. >> reporter: first lady michelle obama, biking with her family today on martha's vineyard. and opening up to parade magazine about raising 15- year-old malia and 12-year- old sasha >> "what i tell my kids is, i'm preparing you for college and for life. so, having independence, knowing how to set your own boundaries, figuring out how to make that balance." >> reporter: asked about these comments to cnn affiliate wcax. >> as a busy single mother - or i shouldn't say single - as a busy mother. >> reporter: the first lady told parade >> "i give my husband credit - he knows who their friends are, he knows what their schedule is. but he's not making the calls to the dance studio to figure out what classes they're taking next year." >> reporter: mrs obama has also made a point of promoting healthy eating - with her own white house garden. and exercise -- often serving as first example -- natpop from first lady vs fallon video? taking on jimmy fallon in a fitness battle and teaching workout moves to kids and the coveted cover model is not above a little vanity as she approaches 50